With each update I lose all bookmarks. Opened this morning with a pretty picture and invitation to donate. I’ll pay ransom to get my saved “stuff” back.
You’ve not mentioned either the Brave version or platform / operating system you’re using.
Since late 2016, I used successive Brave (Muon) versions on Windows 7 (s/p 1) 32- and 64-bit installations. Brave updates were downloaded and installed whether or not I wanted them. This was unacceptable when bandwidth was limited; I rarely used Brave.
Worth mentioning: what I found unacceptable was the inability to control when updates were downloaded but updates never modified or deleted bookmarks or settings. As a backup, I do periodically export and save bookmarks to an .html file.
I recently tried Brave v0.55.22 (Chromium). I found that (consistent with Chrome, Opera, and Vivaldi) I can edit Windows Autoruns. (Also, Firefox users have control over updating.) Updating occurs when I want it. If you’re using Windows, editing Autoruns appears to prevent uncontrolled Brave (Chromium) updates.